Cover Story

A renewable archetype: The power behind Gold Fields’ Agnew mine

What does it take to do mine energy, remotely, renewably, and properly? Elliot Gardner speaks to James Koerting of Gold Fields about making the Agnew gold mine renewable.

Caption: James Koerting on site. Credit: Gold Fields

Gold Fields’ Agnew gold mine is one of the more unique mines in
Australia, with over half of its power coming from a microgrid operated by renewable developer EDL. This gives more than half of the mine’s operations a firm sustainable footing, helping to decarbonise its operations.  

Could this be a blueprint for the future of Australian mining? We spoke to Gold Fields energy manager James Koerting to find out more about the project, and ask whether this technology is scalable elsewhere inside and outside of Australia. 

Elliot Gardner: How did the renewable system at the Agnew gold mine come about, and makes it unique?

James Koerting: So the project’s been operating for two years now, almost three. We had an existing supply agreement that would have expired in 2015/2016, so we started looking into our own independent supplier at the mine site. That was the kick-off for our studies into renewables really. We’d started construction of a solar farm at one of our other mine sites, and we’d begun to be a bit more comfortable working with renewable energy. If you look six or seven years back, renewables were quite new to the mining industry and tended to be seen as a potential risk that could interrupt production.  

Caption: James Koerting at Gold Fields’ mine. Credit: Gold Fields

As clean energy started to emerge properly, there was more of a focus on reducing emissions, and setting targets for getting to net zero by 2050. In 2016/2017 we started looking into potential renewable avenues, and began studies into how we could integrate wind energy into a mine. We knew the first solar project in Western Australia, the DeGrussa Copper Mine, received some government funding. So we started looking into whether we could receive some government funding for this project too in order to help with the risk profile in integrating a new technology. 

Elliot Gardner: How did you decide on the exact renewable makeup of the mine site?

James Koerting: So we started looking into potential partners who could help deliver a project like this. Globally, wind farms tend to be massive, with 100+ turbines, but this project was only five turbines, so very small in comparison. But more than that, we wanted an integrated microgrid that had a gas-fired power station, with a battery and a solar farm as well. So we engaged with groups of companies that could develop a project like this, as well as the federal government through the Australian Renewable Energy Agency, to see how they could support the project. 

We initially approved the gas power station with the solar farm, then partnered with a single development partner to get the wind farm and the battery over the line. We needed both of those deals to go ahead in order to approve the microgrid at Agnew. That process took a little bit of time, but we started construction of the power station and solar farm in 2018 and went into commissioning in the middle of 2019. The wind farm plus battery was constructed in 2019-2020 and those went into commissioning mid-2020. 

The basis of the project was that 54% of the energy that Agnew produced and consumed would be renewable. That increases and decreases seasonally, but that 54% is effectively what we’ve achieved. We do have some technical constraints that mean we can’t run 100% on renewables, but when the winds are high, we can run around 85% renewable at our peak. 

Caption: Wind power in Western Australia. Credit: Travellight.

Elliot Gardner: You mentioned government funding, but was that the main reason for opting for a renewable microgrid?

James Koerting: Gold Fields had a vision in being the global leader in sustainable gold mining, so it certainly cascaded down from a strategic level, but the caveat had to be that it would still be commercially viable. So that’s where the government funding came into things, helping make the project viable. It did need grant funding, and that is very specific to this project as we, and our third party operator EDL, had to recover our investment.  

We made an agreement with EDL that we’d pay off this investment within 10 years, but at that point we only had a gold resource mine life of three years, so there was a bit of a leap of faith there. Today in 2023 we absolutely have that 10 year mine life, so we’ll be mining at Agnew in 2029. So that leap of faith has paid off, but to get Agnew to 10 years required some government funding. 

Elliot Gardner: Mining is perceived as quite a polluting industry, so is this a step toward countering claims of greenwashing, both for Gold Fields and the industry as a whole?

James Koerting: I wouldn’t talk for other mining companies or the mining industry in general as it’s pretty diverse, but it’s absolutely important for Gold Fields. Our building is next door to an oil and gas company, and they have environmental protestors outside the front of their building at least once a week. On the flip side of that, Gold Fields has enjoyed quite a bit of good press and industry accolades for leading on these projects within the mining sector and having a positive perspective to the industry. 

The gold sector is a little fortunate in that we’re not a hugely emitting part of the mining industry because once we produce a gold bar, that’s pretty much a finished product, while iron or copper has a very intense smelting process downstream. 

We’ve set a target to reduce our emissions by a third by 2030. That is becoming an industry norm, and we’ve sought to support other mining companies in achieving their targets or something similar. Agnew effectively achieved its target in 2020, 10 years ahead of schedule. 

Elliot Gardner: How scalable is this technology to other mines? Can other mines in Australia or abroad realistically look to use microgrids for their own projects? 

James Koerting: Solar farms are actually very modular, and so are batteries as well, so all of those components are very scalable. Wind farms don’t scale down so well, however, so you do pay a premium for having a small wind farm. Gold Fields’ target for out here in Australia is having wind farms in all four of our operations by 2030. But that is dependent on whether there’s a positive business case for making such a large investment.  

Agnew’s investment was A$100, but it’s also our smallest mine in terms of power consumption, so it can only get bigger from here. We’re looking at six to 10 turbines for our other mines, and also looking into redeployable solar technology, so if a mine does close, we can pick it up and redeploy it if needed. 

The learnings from Agnew are definitely translating to future projects here, and absolutely this technology is widely deployable. All of our peer companies have the means and the capital to deploy renewables in their mines. Since we built Agnew, I’ve spoken to numerous mining companies doing their own projects in this space, talking about our challenges and how we overcame them, so they’re definitely coming.